湿法磷酸中铁、铝、镁等金属杂质对其下游磷化学品的生产具有极其不利的影响，采用合适的沉淀剂对湿法磷酸进行预处理可简单有效地脱除其中大部分金属杂质。以邻苯二甲酸为沉淀剂对湖北某企业浓缩湿法磷酸进行净化除杂，考察了邻苯二甲酸用量、反应时间和搅拌速率对各杂质离子去除效率的影响。结果表明，当邻苯二甲酸用量为理论值的1.5倍、搅拌线速度为0.2 m/s、常温反应40 min时，湿法磷酸中Fe³⁺、Mg²⁺、Al³⁺和Ca²⁺的脱除率分别达到了68.94%、55.18%、53.02%和46.9%，反应后磷酸中P₂O₅质量分数仅下降了2.5%，展现出较好的应用前景。

Metal impurities in wet-process phosphoric acid, such as iron, aluminum and magnesium, have significantly negative impacts on production of phosphoric acid-derived chemicals, most of which can be effectively removed by using suitable precipitants in pretreatment.In this contribution, o-phthalic acid is utilized as precipitant to purify the concentrated wet-process phosphoric acid produced in a plant in Hubei province, China.The influences of the addition amount of o-phthalic acid, reaction time and stirring speed on the removal rate of metal impurities are investigated experimentally.It is shown by the results that the removal rates of Fe³⁺, Mg²⁺, Al³⁺ and Ca²⁺ reach 68.94%, 55.18%, 53.02% and 46.9%, respectively and the concentration of phosphorus pentoxide in the purified phosphoric acid decreases by only 2.5% when the addition amount of o-phthalic acid is 1.5 times the theoretical one, stirring linear velocity is 0.2 m·s^-1 and the reaction lasts for 40 minutes at room temperature.The results indicate a good practical prospect.

陈以明(1972-),男,学士,工程师,主要从事湿法磷酸生产与技术研发,dyk.cym@163.com。